A large liquid crystal display device is used as, for example, a display device for amusement facilities, an information display, or digital signage. As the range of uses increases, trials have been conducted of pseudo large screen display devices by arraying multiple liquid crystal display devices (may also be referred to as a tiling technique). A large screen display device having such a configuration is called, for example, a multi-display system. Such a multi-display system, however, has a problem of there being noticeable joints between the multiple display devices.
This problem will be described by taking a liquid crystal display device as an example. A liquid crystal display device includes a liquid crystal display panel, a backlighting device, a circuit and a power source that supply various electric signals to the liquid crystal display panel, and a housing in which the display panel, the backlighting device, the circuit, and the power source are accommodated. The liquid crystal display panel has a display area, in which multiple pixels are arrayed, and a frame area around the periphery of the display area. Pixel electrodes and thin film transistors (TFTs) are arranged in the display area. Components such as a sealing portion, with which a liquid crystal material is sealed between boards, and a driving-circuit mounting portion are arranged in the frame area. Since pixels are not arrayed in the frame area, the frame area does not contribute to display. Although frames of liquid crystal display devices have been progressively made smaller year by year, it is fundamentally impossible to eliminate a frame area.
In a multi-display system formed by tiling multiple liquid crystal display devices, the frame areas of adjacent liquid crystal panels are arranged adjacent to each other, thereby generating joints, at which an image cannot be displayed, at the border between the panels. In view of this circumstance, PTLs 1 and 2 each disclose a display device including a light-transmitting cover disposed on a viewer side of each display panel to display a jointless image.
A viewer-side edge portion of the light-transmitting cover has a curved surface. Since the portion having the curved surface functions as a lens, this portion may also be referred to as a “lens portion” below. The lens portion of the light-transmitting cover is arranged so as to overlap the frame area of the display panel and part of the display area adjacent to the frame area. The part of the display area that is overlapped by the lens portion is referred to as a peripheral display area. Light emitted from pixels arrayed in the peripheral display area is refracted by the lens portion arranged in the frame area in accordance with the shape of the lens surface. Consequently, an image is also displayed on the front side of the frame area and thus a jointless image is displayed over the entire area of the screen.
FIG. 1 illustrates the state in which two liquid crystal display devices 900 each having the above-described light-transmitting cover are arranged adjacent to each other. As illustrated, light-transmitting covers 902 are disposed on the display surface side of the two liquid crystal panels 904 arranged side by side. Each light-transmitting cover 902 includes a flat surface portion 924 and a curved surface portion 922, which is located at the edge of the flat surface portion 924 and functions as a lens. Light emitted from backlights 906 is transmitted through the liquid crystal panels 904 and then refracted by the curved surface portions 922 of the light-transmitting covers 902 and emerges toward a viewer. Since the viewer cannot see the frame areas 910F (non-display areas) located on the outer side of the display areas 910A, the screens of the two display devices appear to be continuous with each other.